Sumitron marketing provides double-acting meters and mixing systems [model 2500-da] from i & j fisnar inc, usa. Filler substances are added to primary materials for several reasons, including thickening agents, accelerators, sg agents, dielectric compounds, conductivity and many more. Many materials that use fillers are two-part substances requiring metering and mixing. A suitable machine for two-part viscose compounds containing abrasive filler is model 2500-da. The system is a positive displacement machine capable of reducing wear due to its double-acting design and abrasion resistant metering cylinders and seals. The double-acting inline design reduces stress caused by high viscosity fluids and delivers on-demand dispensing without interruption for reloading the metering cylinders. The 2500-da effectively doubles the life expectancy of seals by reducing the recharge cycles necessary during dispensing. The system uses 4-way flow directional valves [not check valves] for maintaining very accurate flow ratios. In selecting a suitable dispensing system for an application that uses a substance with a filler additive, it is important to pay close attention to the material specification and the nature of the filler, whether the filler is abrasive or simply a talc thickening agent. The type of dispensing metering system will be selected from this information and an appropriate construction chosen.